Since the description of the first proto-oncogenes Src, Myc, Jun and Ras, many other oncogenes and tumor suppressor genes have been identified. The respective proteins regulate key cellular growth and death pathways. Dysregulation allows oncogenes and tumor suppressor genes to transform mammalian cells and cancers arise in conditions where multiple such events are juxtaposed. Many proto-oncogenes and tumor suppressors have been mapped to canonical signaling pathways, providing a more holistic view of growth control mechanisms and paving the way for systems level analysis of cancer mechanisms.